1. Field of the Invention
The present invention relates generally to beds, and more particularly to a bed convertible from a sofa and including knock-down features.
2. Description of the Prior Art
A considerable number of sofas convertible to beds have been proposed by prior art workers. The vast majority of these sofa beds operate either foldably, where a plurality of sections are hingedly connected so that the sofa can be converted to a bed by a complex series of horizontal and vertical motions, or extensibly where the sections are withdrawn linearly to provide a planar sleeping surface.
The foldable sofa beds, although having enjoyed the greatest commercial success, require rather complicated operating mechanisms which greatly contribute to the weight of the unit and its manufacturing cost. In addition, since sofa beds of this type generally require a lifting motion, they cannot be used by persons unable to perform heavy lifting. Finally, the mattress overlying the sleeping or sitting surface of foldable sofa beds must undergo considerable bending which greatly reduces the life of the mattress and can further result in damage to the mattress resiliency which makes sleeping or sitting an uncomfortable experience.
Extensible sofa beds have also suffered from similar drawbacks. For example, complex guide mechanisms must be employed to insure that the extensible sections do not jam when the unit is being opened or closed. This problem is due partly to the considerable weight of the operating members. Attempts to reduce the weight of the operating members by eliminating structural material by constructing the sofa bed of lighter weight material have generally resulted in furniture of flimsy construction or increased cost. In addition, the operating mechanisms joining the extensible sections are usually wheels or rollers which are subject to wear and can easily slip from their guiding track, thereby rendering the bed mechanism inoperable.
Conventional extensible sofa beds are generally constructed such that the stationary section is supported entirely by the arms and/or back of the sofa. Hence, the supporting members must possess sufficient structural strength to support the weight of persons seated on the sofa or lying on the sofa bed when it is extended. This, of course, contributes to the overall weight and cost of the unit. In addition, since the stationary section is supported entirely by the arms and/or back of the sofa bed, these members cannot be easily removed for storage or shipment. Although knock-down sofa beds have been proposed, the additional expense of reassembling the mechanically complex units generally outweighs any cost savings experienced in lower shipping costs produced by higher packing densities of the knock-down units.
Finally, prior art extensible sofa beds have not completely solved the problem of mattress storage when the apparatus is not being used as a bed. Some designs have included a multiple section mattress which can be manually stacked when the sofa bed is being used as a seating unit. However, this arrangement results in a seating surface which is positioned at an uncomfortable height from the ground. In addition, inasmuch as the modern emphasis of furniture designers is on low silhouette sofa units, the aesthetic features of such designs are lacking.